Approximate impulse signals producing device of the pneumatic pressure type

ABSTRACT

An approximate impulse signal producing device of the pneumatic pressure type comprising a casing, a rotor supported in said casing and formed on its outer peripheral surface with a surface inclined with respect to the direction of rotation of the rotor, a pressure supply duct provided in said casing for ejecting an air jet under pressure to said inclined surface of the rotor, a drain provided in said casing in a position substantially symmetrical to the position of said pressure supply duct, and an output duct provided in said casing and disposed substantially midway between said pressure supply duct and said drain.

ilie Sites isliida [54] APPROXIMATE IMPULSE SIGNALS PRODUCING DEVICE OF THE PNEUMATIC PRESSURE TYPE Takashi lshida, Ohi-Machi, Japan Mlkuni Kogyo Co., Ltd., Tokyo, Japan Nov. 23, 1970 Inventor:

Assignee:

Filed:

Appl. No.:

Foreign Application Priority Data Nov. 22, 1969 Japan ..44/938l5 Oct. 23, 1970 Japan ..45/93372 U.S.Cl. ..l37/83, 73/521, 116/137A ...Fl5b 5/00, GOlp 3/26, GlOk 5/00 ..l37/8l.5, 82, 83; 116/137 A;

References Cited UNITED STATES PATENTS l/l954 Smith ..116/137A o t put 51 at. 2,718,878 9/1955 DuBois "137/82 3,011,505 12/1961 Reip ..137/83 3,216,248 11/1965 Halloway ..73/506 3,392,739 7/1968 Taplinetal. ....73/521 3,489,014 1/1970 Przybylko... ....73/521 3,503,479 3/1970 Canova ..73/521 Primary Examiner-Henry F. Raduazo Attorney-McGlew and Toren [5 7] ABSTRACT An approximate impulse signal producing device of the pneumatic pressure type comprising a casing, a rotor supported in said casing and formed on its outer peripheral surface with a surface inclined with respect to the direction of rotation of the rotor, a pressure supply duct provided in said casing for ejecting an air jet under pressure to said inclined surface of the rotor, a drain provided in said casing in a position substantially symmetrical to the position of said pressure supply duct, and an output duct provided in said casing and disposed substantially midway between said pressure supply duct and said drain.

3 Claims, 6 Drawing Figures PATENTEDMAR28 I972 3 651,824

I sum 1 BF 2 Fig.

out put 1 INVENTOR. TAKASM ISH 1BR PATENTEMAR28 I972 23, 651 ,824

min 2 OF 2 6U 50 out put k 2 n out put kg/cm2 rotor rev. angle rad.

Fig.5 Fig.6

17 out put kg/cm 'U out put kg 2 rotor rev.angle rad. rotor rev. angle rad.

INVENTOR. TAKASH! ISHHDA APPROXIMATE IMPULSE SIGNALS PRODUCING DEVICE OF THE PNEUMATIC PRESSURE TYPE This invention relates to an approximate impulse signal producing device of the pneumatic pressure type.

Heretofore, it has been customary to employ pneumatic pressure to prepare various signal circuits for use as control means. A one-shot circuit has often been used in a control circuit. In such a case, there is no trouble if the one-shot output has a sufficiently great width. However, when said width of the one-shot output is very small, a trigger input signal to the oneshot circuit must have a very small width which should never exceed the width of the output signal thereof. When this is the case, a trigger input signal must be adjusted beforehand by various operation circuits so as to have a very small width.

An object of the present invention is to provide a device for positively producing by mechanical means approximate impulse wave forms to be used as trigger signals in such a case without using operation and setting circuits.

The aforementioned object of the invention is accomplished by providing a device for producing approximate impulse signals which is characterized by the fact that a rotor having a planar surface which is inclined with respect to the direction of its rotation is supported in a casing, said planar surface of the rotor being provided with a pressure supply duct for permitting an air current under pressure to be ejected therethrough and with a drain in a position substantially symmetrical to that of the pressure supply duct, and an output duct is provided between the pressure supply duct and the drain.

The device of the aforementioned nature according to this invention permits to produce approximate impulse signals of any width as desired and deliver them through the output duct by varying the amount of air drained away through the drawing. The invention is useful in simplifying circuits in various control apparatus and increasing their dependability and reducing their cost of production. I

An embodiment of the invention will now be described with reference to the drawings. A casing consists of a portion 11 which provides cover to a shaft 13 journalled by a bearing 19 and a major diameter portion 20 which contains therein a rotor 14 attached to the forward end of the shaft 13. A cover 15 is secured by means of screws 16 to an end surface of the major diameter portion which is formed in its interior with a disc-shaped chamber 12 for housing the rotor 14 therein. The chamber 12 is segregated from outside and sealed airtight by an O-ring 18 mounted between the cover 15 and major diameter portion 20 and an air seal 17 mounted on the shaft 13.

As shown in FIG. 2, an air supply duct 25, output duct 26 and drain 27 are formed in the major diameter portion 20. The air supply duct is disposed on the wall of the disc-shaped chamber 12 removed from the center of the rotor 14 in a position in which an incoming air current is incident on the rotor 14 substantially tangentially thereto, and the drain 27 is disposed coaxially with and opposite to the air supply duct 25. The output duct 26 is disposed at right angles to the line connecting the air supply duct 25 and drain 27.

The drain 27 is formed with a drain port 28 in its wall and mounts an adjusting screw having a needle 29 for regulating the amount of air drained away through the drain port.

The rotor 14 has a spiral curved surface portion B which gradually increases its radius from a point A till its radius is maximized at a point C. The rotor has an inclined planar surface D which extends approximately normal to the cam axis. It should be understood that the present invention is not limited to the specific form of the rotor 14 shown, and-that rotors of other cam form such as leaf cam, spiral cam and the like may be used instead.

If there were no rotor 14, an air jet from the air supply duct 25 would proceed direct to the drain 27 and vented to atmosphere through the drain port 28. The presence of the rotor 14 of the shape described will cause the air jet supplied from the air supply duct 25 to be traversed by the inclined surface D so as to produce an impulse signal for each one complete revolution of the rotor 14 and send out the same through the output duct 26.

In this way, the rotation of the rotor 14 in the direction of the arrow in FIG. 2 produces approximate impulse signals which are under the influence of a certain bias pressure as shown in FIG. 3. In FIG. 3, if the angles of rotation of the rotor 14 set forth along the transverse axis are plotted against the outputs in kgJcm. set forth along the vertical axis. it will be possible to produce at regular intervals output pulses of relatively high magnitude in irregular pulsating waves when the rotor 14 is rotated at a constant rate. The output waves may vary depending on the shape and configuration of the rotor, the pressure of air and the rate of revolution of the rotor. With the cam disc of the type described, it is possible to produce impulse waves in a range from 600 to 12,000 r.p.m.

The lower curve in FIG. 3 shows the production at regular intervals of approximate impulses on the base of a bias pressure P when the apperture of drain port 28 is fully open whereas the upper curve in FIG. 3 shows the production of approximate impulses when the aperture of drain port 28 is throttled to increase the bias pressure to P,,. It will be seen that by varying the amount of air vented through the drain port by means of the adjusting screw 30 it is possible to produce as output signals impulse signals which are under the influence of a certain bias pressure.

The output signals described above are each produced when the air jet supplied through the air supply duct 25 impinges on the inclined planar surface D of the rotor which reflects and directs the air jet toward the output duct 26. The width t of each of the output signals corresponds to the time required for a reflecting point (the projection C, for example) on the inclined planar surface of rotor 14 to pass by the aperture of output duct 26. After the reflecting point (the projection C, for example) has passed by the aperture of output duct, the air jet supplied through the air supply duct 25 is scattered in the chamber 12 of the casing 10, thereby increasing the pressure in the chamber. The rotor 14 is of spiral shape as shown and has a wall which has a thickness greater than the diameter of the ducts 25, 26 and 27. With this arrangement, the amount of air supplied through the air supply duct 25 and delivered direct to the drain 27 increases gradually as the rotor 14 rotates, so that the internal pressure in the chamber does not rise in proportion to the angle of rotation of the rotor and is maintained constant.

FIG. 4 shows the production at regular intervals of approximate impulses of an amplitude h and a width 1, under the influence of a bias pressure P when the pressure under which the air jet is supplied is medium, the throttling of the drain is medium and the diameter of output duct is large. If the diameter of output duct 26 is reduced when other conditions remain unchanged, the amplitude h of impulses will be reduced under the bias pressure P P, and the period of time I, required for pulses to rise and fall will be reduced too as shown in FIG. 5. If the pressure under which the air current is supplied is increased, the bias pressure P and the amplitude h of pulses will be increased as shown in FIG. 6. It will thus be apparent the shape of approximate impulse signals and the degree of bias pressure can be selected considerably freely as desired.

From the foregoing description, it will be appreciated that the approximate impulse signal producing device according to this invention permits to readily produce approximate pulses of a relatively high amplitude under the influence of a suitable bias pressure. Thus, the device according to this invention can be used as an impulse producing element of an operation circuit of the pneumatic pressure type or a rotary sensor. This makes it possible to do without a conventional impulse producing circuit and bias circuit of the large type and to obtain an overall compact size in an operation circuit as a whole.

What is claimed is:

1. An approximate impulse signal producing device of the pneumatic pressure type comprising a casing, a rotor supdisposed substantially midway between said pressure supply duct and said drain.

2. A device as defined in claim 1 wherein said inclined surface is planar.

3. A device as defined in claim 1 wherein a throttle valve is provided in said drain. 

1. An approximate impulse signal producing device of the pneumatic pressure type comprising a casing, a rotor supported in said casing and formed on its outer peripheral surface with a surface inclined with respect to the direction of rotation of the rotor, a pressure supply duct provided in said casing for ejecting an air jet under pressure to said inclined surface of the rotor, a drain provided in said casing in a position substantially symmetrical to the position of said pressure supply duct, and an output duct provided in said casing and disposed substantially midway between said pressure supply duct and said drain.
 2. A device as defined in claim 1 wherein said inclined surface is planar.
 3. A device as defined in claim 1 wherein a throttle valve is provided in said drain. 